c.500ml

D.125ml

n)x³-2x²+x-2=(x³-2x²)+(x-2)=x²(x-2)+(x-2)=(x-2)(x²+1)

x²-5x=x(x-5)

h)x²-4x+4=(x-2)²

g)x³-125=(x-5)(x²+5x+25)

c)4x²+12x+9=(2x+3)²

d)(x-y)²+3(x+y)²=x²-2xy+y²+3(x²+2xy+y²)=x²-2xy+y²+3x²+6xy+3y²=4x²+4xy+4y²

a) -x²+6x-9=-(x²-6x+9)=-(x-3)²

b)(x+1)²-(2x+3)²=(x+1-2x-3)(x+1+2x+3)=(-x-2)(3x+3)

e)x³-x²+x-1=0

\(\Rightarrow\)(x³-x²)+(x-1)=0

\(\Rightarrow\)x²(x-1)+(x-1)=0

\(\Rightarrow\)(x-1)(x²+1)=0

\(\Rightarrow\)x-1=0 hoặc x²+1=0

\(\Rightarrow\left[{}\begin{matrix}x-1=0\\x^2+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x^2=-1\left(KTĐTSx\right)\end{matrix}\right.\)

KTĐTSx: không tìm được thừa số x

Vậy S={1}